The present invention relates to an optical guide fixture for coupling visual information on a surface to an optical viewer. More particularly, the invention provides an apparatus having such an optical guide fixture for convenient viewing of visual information present on a surface.
A number of devices are known for assisting an individual having a visual impairment to view visual information, such as text and graphics, on a surface. Some such devices employ a scanner, such as a mouse-like device, having an optical receiver therein to obtain data corresponding to the visual information on the surface, and to transmit the data to a closed circuit television (CCTV) to be viewed on a television monitor. For example. U.S. Pat. No. 5,046,163 describes such a device. Such conventional devices are typically bulky, and hence are not easily portable. Further, an individual employing such a device can not easily determine which portion of the surface is being shown on the monitor because the scanner partially obstructs the surface. In addition, the scanner of such a device is typically bulky and hence is not suitable for scanning areas of the surface that are not easily accessible, such as the border areas between two adjacent pages of a book.
Another conventional system includes a head-mounted display unit coupled to a camera for viewing visual information on a surface. Such a system typically does not provide a mechanism for conveniently aiming the camera at a selected portion of the surface. This can lead to confusion, especially for a visually-impaired patient, regarding which portion of the surface is being viewed. In addition, a person other than the viewer can not easily determine which portion of the surface is being viewed. This is particularly disadvantageous in an educational setting, for example, where an instructor is helping a patient read a book. In addition, such systems are typically heavy, and are cumbersome to wear.
Another conventional system, described in U.S. Pat. No. 4,330,169, includes a scanning head coupled to a bundle of optical fibers. A visually impaired individual views a portion of a surface bearing visual information by looking through a telescope that is coupled to the optical fibers. The scanning head of this device has a relatively narrow field of view. Further, the field of view of the fibers and that of the scanning head are different. Further, the scanning head of this patent is rotationally symmetric, thereby rendering rotational alignment of the scanning head relative to the surface and/or guided translation of the scanning head along a selected direction over the surface difficult. Another defect of the system of the '169 patent is that the telescope does not follow the movements of the patient's head. Accordingly, the patient must keep the head stationary relative to the telescope in order not to lose the view of the surface. This can lead to fatigue and renders viewing of the surface over a long period inconvenient.
Thus, it is an object of the invention to provide an optical guide fixture for conveniently scanning a surface bearing visual information, to couple the visual information to an optical receiver.
It is another object of the invention to provide an optical guide fixture that can be conveniently rotationally aligned relative to a surface.
It is another object of the invention to provide a portable device for aiding a visually impaired patient to view visual information on a surface.
It is yet another object of the invention to provide a device for aiding a visually impaired patient to view information on a surface, which is light weight and easy to wear.